Chassis amp grounding vs. running ground back to battery

[audiolife 5,000+ posts]

depends on the type of vehicle as trucks generally have a full frame and most cars are now UNIBODY and dont have a full frame. never had a noise issue grounding at the battery either and since when do caps carry huge amounts of current? LOL I know Sound stream recomends grounding anything over 500 watts back to the battery least they did in all my SS manuals.

 

[dwc 10+ year member]

but for dd, just ground to frame

Not sure what dd means in this context. The amp company?

I am going to buy the needed stuff to ground back to batt if I need to, and then do some testing with the Fluke.

thx

p.s. Any better deals/quality than the Knu amp kits? Seems better to me than the stinger kits on ebay.

 

[azbass 5,000+ posts]

resistance

nuff said

 

[DejaWiz 5,000+ posts]

Not sure what dd means in this context. The amp company?

Daily driver.

 

[atoz350 10+ year member]

Well my battery is in the trunk of my car, so, it only made sense to ground at the battery.

 

[helotaxi 5,000+ posts]

Unless you have one hell of a nice DMM (most Fluke meters aren't good enough if that helps any) you should not be able to measure the resistance of your ground if it is a good one. It will be below the measurable limits of the meter and well smaller than the meter's error tolerance.

The reason I advocate going back to the battery is one of reliability and repeatability. The only way to find a good ground on the chassis of a unibody car is by trail and error. The first spot you try might be fine, it might be the 20th. There are only so many pre-existing bolts on the car to try before you find yourself drilling holes for grounds. In the mean time you could have simply run a cable the same size as your positive wire at the same time as your positive wire, connected it to the battery and called it good. You know exactly the amount resistance and voltage drop for your ground and you know that the answer for both is "negligible."

That said, for lower powered systems with lower current draw, i.e. those only needing a single run of 4ga wire for the positive wire for the whole system, a chassis ground works just fine.

As far as the battery being a "noisy" ground...impossible. It's a point of ZERO potential. Noise is caused by voltage. Zero potential means zero voltage means zero noise. By running a dedicated ground you avoid the possibilty of getting shared ground path noise completely because the only common path in the ground between your amps and any other piece of electrical equipment is the zero potential point.

 

[Ignatowski 5,000+ posts]

wow,alot of ignorant opinions on this thread.........

 

[PSturmer 10+ year member]

Unless you have one hell of a nice DMM (most Fluke meters aren't good enough if that helps any) you should not be able to measure the resistance of your ground if it is a good one. It will be below the measurable limits of the meter and well smaller than the meter's error tolerance.
The reason I advocate going back to the battery is one of reliability and repeatability. The only way to find a good ground on the chassis of a unibody car is by trail and error. The first spot you try might be fine, it might be the 20th. There are only so many pre-existing bolts on the car to try before you find yourself drilling holes for grounds. In the mean time you could have simply run a cable the same size as your positive wire at the same time as your positive wire, connected it to the battery and called it good. You know exactly the amount resistance and voltage drop for your ground and you know that the answer for both is "negligible."

That said, for lower powered systems with lower current draw, i.e. those only needing a single run of 4ga wire for the positive wire for the whole system, a chassis ground works just fine.

As far as the battery being a "noisy" ground...impossible. It's a point of ZERO potential. Noise is caused by voltage. Zero potential means zero voltage means zero noise. By running a dedicated ground you avoid the possibilty of getting shared ground path noise completely because the only common path in the ground between your amps and any other piece of electrical equipment is the zero potential point.

thank you, x2

 

[SPL Blazer 10+ year member]

If your doing this to a daily driver than there's not much of a point in spending the extra money on the wire to run a ground to the front battery. It's a great option if you have the extra money to throw away, but not necessary. A run of copper ground wire is going to have a lot less resistance than just grounding to the frame, doesn't matter where you ground it this fact isn't going to change. If your not competing then the difference will most likely never be noticed. I ran a single run of 0/1 (+) to my rear battery and grounded to the frame for over a year, then added a run of the same thread count 0/1 as a ground from the front battery to the rear one and didn't ground to the chassis in the rear and never noticed a difference. I do competitions and only noticed the difference when I was on the meter, I gained .3 db by adding the extra run of 0/1 ground. With a daily system you would never notice this difference.

 

[bimmer328]

I think the real question to those who go to the battery is why? Are you having trouble grounding to the frame/body? Inducing noise?

I'm just trying to understand why people go this route.

With my experience I have a 09 bmw so not only is my ground 3ft but it’s running straight off the battery too. So I was looking to see what ppl had to say bc BMW’s use the battery for so much of the cars features…

 

[Popwarhomie 5,000+ posts]

With my experience I have a 09 bmw so not only is my ground 3ft but it’s running straight off the battery too. So I was looking to see what ppl had to say bc BMW’s use the battery for so much of the cars features…

16 year old thread bump...

 

[mahc 10+ year member]

All non-sens. Everybody knows the best grounding spot is on the prince albert ring.

 

[Mitchell Fosgate III]

Can I get some advice on this? This is my rookie install and I have read some that say you ground the amps to chassis close to the amp, and then I read about others who run a ground wire all the way back to the battery. What about doing both via a distro block?

Not a closed loop. You would not need to run it back to the distribution block. Along the car chassis and close by would do it. Any shortage of the amps will go directly to the chassis, then directly to the ground. Tires. Will not hit any of the passengers. If some thing were to happen while the amplifier is on. A short circuit some where. Plus there's the rug above the chassis to insulate the wiring when you connect it to the chassis ground. And the electrical tape used to insulate it. Wrap it around the cable and run it along the car chassis ground.

One last thought: What kind of shortages would occur? A differential ampliflier such as the OP AMP, have also a inverting amplifier and a summing amplifier circuits. By connecting resistors in parallel to the negative inputs, on the bypass which you may have, the OP AMP acts as a voltage amplifier. Such as the negative and a parking brake green wire is. Voltages add up to give the circuit added functions. Your DVD for example is back on. This bypass is explained in the summing amplifier. Called a negative feedback on the inverting input. Pin slots to pin slots, jump a pin or two. ISO Connections

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[spokey9 5,000+ posts]

Not a closed loop. You would not need to run it back to the distribution block. Along the car chassis and close by would do it. Any shortage of the amps will go directly to the chassis, then directly to the ground. Tires. Will not hit any of the passengers. If some thing were to happen while the amplifier is on. A short circuit some where. Plus there's the rug above the chassis to insulate the wiring when you connect it to the chassis ground. And the electrical tape used to insulate it. Wrap it around the cable and run it along the car chassis ground.​

TF are you even trying to say?

 

[spokey9 5,000+ posts]

Not a closed loop. You would not need to run it back to the distribution block. Along the car chassis and close by would do it. Any shortage of the amps will go directly to the chassis, then directly to the ground. Tires. Will not hit any of the passengers. If some thing were to happen while the amplifier is on. A short circuit some where. Plus there's the rug above the chassis to insulate the wiring when you connect it to the chassis ground. And the electrical tape used to insulate it. Wrap it around the cable and run it along the car chassis ground.​

TF are you even trying to say?